OFDM or COFDM is a multicarrier modulation technology where the available transmission channel bandwidth is subdivided into a number of discrete channels or carriers that are overlapping and orthogonal to each other. Data are transmitted in the form of symbols that have a predetermined duration and encompass some number of carried frequencies. The data transmitted over these OFDM or COFDM symbol carriers may be encoded and modulated in amplitude and/or phase, using conventional schemes.
In harsh environments and especially mobile environments, a received signal undergoes signal degradation and in particular, the received signal is submitted to co-channel reception, i.e. the signal is submitted to spurious frequency noise also called frequency anomalies due to other signals transmitted in the same channel.
In known devices, the received signal is converted into a base band digital signal. These operations are achieved in a conventional way by an analog front end tuner. The signal is then processed to estimate the phase and gain mismatch for ulterior compensation.
However, in the known devices, the co-channel signals are not dealt with and accordingly, the estimation of phase and gain mismatch is biased, leading to an incorrect estimation and thus an incorrect correction.
Therefore, it is desirable to develop a new method and a corresponding device to estimate the phase and gain mismatch of a base band digital signal in order to improve the quality of the estimation, especially under co-channel conditions.